The S&P 500 has risen about 12% so far in 2026, but three of its largest components, Microsoft, Alphabet, and Amazon, have lagged behind. Microsoft is up around 8%, Amazon about 7%, and Alphabet's Class A shares just 2%. Together, these three tech giants make up about 15% of the index.
All three companies are set to report their quarterly earnings within two days of each other: Microsoft and Alphabet on October 28, and Amazon on October 29. These reports could significantly impact S&P 500 funds, as the three stocks together represent around 15% of such funds. Historically, their earnings reports have triggered substantial price movements, with each stock moving 10% or more the day after at least one of their reports this year.
Despite their underperformance, the S&P 500 has still managed a solid year. Apple and Nvidia, which together make up about 15.5% of the index, have contributed more to the index's gains than Microsoft, Alphabet, and Amazon combined. The upcoming earnings reports could either narrow or widen the performance gap between these tech leaders and the broader market.
For investors holding S&P 500 funds, the earnings reports from these three companies will be a critical test. Even if all three stocks repeat their July post-earnings movements, the impact on the fund would be relatively modest, around a 1% change. However, given the concentration of these stocks in the index, their performance remains a key focus for market watchers.